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Arctic System Reanalysis (ASR)

The Arctic System Reanalysis is a multi-agency, university-led retrospective analysis (reanalysis) of the Greater Arctic. ASR is produced using high-resolution versions of the Polar Weather Forecast Model (PWRF) and the WRF-VAR and High Resolution Land Data Assimilation (HRLDAS) data assimilation systems that have been optimized for the Arctic. ASR is a comprehensive integration of the regional climate of the Arctic, currently for the period 2000-2012, with two versions: ASRv1 – 30 km and ASRv2 – 15 km; both are available through the NCAR Research Data Archive. Both versions have 29 pressure levels (71 model levels), 27 surface and 10 upper air analysis variables, 74 surface and 16 upper air forecast variables, and 3 soil variables. Both the u- and v- winds relative to grid and relative to earth are present in the final version.

New features in ASRv2 compared to ASRv1 are higher horizontal resolution, updated model physics including sub-grid scale cloud fraction interaction with radiation, and a dual outer loop routine for more accurate data assimilation. Surface and pressure level products are available at 3-hourly and monthly-mean timescales. ASRv2 will be updated through 2016, then re-assimilated (2000-2016) using the most recent version of Polar WRF and WRFDA (3.9.1). This newer version, ASRv2.1, should be available starting in mid-2018 and will be kept up-to-date through 2020 with a delay of ~3 months. [text credit: Aaron Wilson and David Bromwich]

Key Figures

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Thumbnails

Captions

Figure 1: ASR inner and outer domains with terrain height (shaded). The number of grid points in each direction and horizontal resolution are provided in the top-right (lower-left corner) for ASRv2 (ASRv1). (contributed by A. Wilson)

Figure 2: Comparison showing left) ASRv2 mean 700 hPa relative humidity (%) and right) difference (%) between ASRv2 and ERAI for the period December 2006 – November 2007. Where the 700 hPa pressure level exists below ground based on the annual average surface pressure have been masked in gray. (contributed by A. Wilson)

Figure 4: Streamlines and wind speeds (colors) at 10-m for an intense orographically channeled wind event in Nares Strait on 9 February 2007 as captured by a) ASRv1 and b) ASRv2. Orographic channeling in Nares Strait may help generate persistent winter North Water polynya. ASRv2 resolves the orography of Nares Strait and thus the winds are much stronger (> 20 m s-1 ) and more continuous than ASRv1 (~15 m s-1). The katabatic winds over Greenland feed into the wind flow at two locations in ASRv2. There are multiple centers in the low over Baffin Bay in ASRv2 compared to the single center in ASRv1. (contributed by A. Wilson)

Cite this page

National Center for Atmospheric Research Staff (Eds). Last modified 09 Nov 2017. "The Climate Data Guide: Arctic System Reanalysis (ASR)." Retrieved from https://climatedataguide.ucar.edu/climate-data/arctic-system-reanalysis-asr.

Acknowledgement of any material taken from this page is appreciated. On behalf of experts who have contributed data, advice, and/or figures, please cite their work as well.

Arctic System Reanalysis (ASR)

The Arctic System Reanalysis is a multi-agency, university-led retrospective analysis (reanalysis) of the Greater Arctic. ASR is produced using high-resolution versions of the Polar Weather Forecast Model (PWRF) and the WRF-VAR and High Resolution Land Data Assimilation (HRLDAS) data assimilation systems that have been optimized for the Arctic. ASR is a comprehensive integration of the regional climate of the Arctic, currently for the period 2000-2012, with two versions: ASRv1 – 30 km and ASRv2 – 15 km; both are available through the NCAR Research Data Archive. Both versions have 29 pressure levels (71 model levels), 27 surface and 10 upper air analysis variables, 74 surface and 16 upper air forecast variables, and 3 soil variables. Both the u- and v- winds relative to grid and relative to earth are present in the final version.
New features in ASRv2 compared to ASRv1 are higher horizontal resolution, updated model physics including sub-grid scale cloud fraction interaction with radiation, and a dual outer loop routine for more accurate data assimilation. Surface and pressure level products are available at 3-hourly and monthly-mean timescales. ASRv2 will be updated through 2016, then re-assimilated (2000-2016) using the most recent version of Polar WRF and WRFDA (3.9.1). This newer version, ASRv2.1, should be available starting in mid-2018 and will be kept up-to-date through 2020 with a delay of ~3 months. [text credit: Aaron Wilson and David Bromwich]

The National Center for Atmospheric Research is sponsored by the National Science Foundation. Any opinions, findings and conclusions or recommendations expressed in this material do not necessarily reflect the views of the National Science Foundation.